algebra 1 6 dec 2011 1) put papers from your group folder into your binder. 2) put your binder, hw...

Algebra 1 6 Dec 20111) Put papers from your group folder into your binder.2) Put your binder, hw and text on your desk. START WU.ONLY weekly WU and daily CW in folder. ONLY weekly WU and daily CW in folder.

CHECK YOUR HOMEWORK √ or X each problemCHECK YOUR HOMEWORK √ or X each problem

WARM UP- Solve and checkWARM UP- Solve and check1) 2x – 5 = 121) 2x – 5 = 122) 2(x – 5) = 202) 2(x – 5) = 203) 4x + 5x + 6 = 243) 4x + 5x + 6 = 244) 3 – 2(x+3) = 94) 3 – 2(x+3) = 9

Objective

Students will be create and interpret a scatter plot and find the equation of the line of fit.

Students will take notes and use think-pair-share.

homework due todaypg. 244: 1, 2, 3

homework due next classfinish your scatter plot ½ sheet

both sidesSTUDY for QUIZ on finding

equations

finding equations

1. WHERE does it START? (y value when x = 0)2. INCREASING OR DECREASING?3. BY HOW MUCH EACH TIME? Slope!!

review- how can you find slope?

Look in your yellow page notes.1) how do you find slope using a slope triangle?2) slope from a table?3) what is the slope triangle?

slope using a slope triangle

1 2 3 4 5 6 7 8 9 days

5

10

15

20

25

30

35

40

45

50apples

over 5

down 20

1. pick two GOOD points2. Draw one horizontal arrow and one vertical angle to connect the two pointsto make a TRIANGLE

3. Count the spaces- remember SCALE!!

SLOPE = 204

5

40 4equation y x

equation from 2 points-- use a tableexample: find the slope between (4,12) and (6,16)

x y4 126 16

+2 +4

x y

4 126 16

1. Put the points in a table

2. find the differences in x and y values

SLOPE = 4

22

rise y

run x

4. extend tableto find y-intercept

20

8

4

EQUATION y = 4 + 2x

(x1, y1)

(x2, y2)x yx1 y1

x2 y2

(y2-y1)(x2-x1)

2 1

2 1

y ym

x x

y2

y1

x2x1

slope formula

Developing the slope formula

y2-y1

x2-x1

1 2 3 4 5 6 7 8 9 x

2

4

6

8

10

12

14

16

18

20y

find y-intercept when given two points(4, 12) and (6,16)

extending the line backwards can give us an ESTIMATE…but it is EASY to be “off” and not get the exact value

1. plot the two points

2. draw your slope trianglewe went up 4, over 2 (watch scale)

3. now go backwards, making slope triangles until you get to the y- intercept DOWN 4, LEFT 2 (- divide by - = +)

Scatter Plots1. Scale your axises. Plot the points. 2. Draw a line of best fit.3. Identify the y-intercept?4. Find slope.Choose two GOOD points on your LINE (NOT

necessarily FROM THE DATA TABLE) and calculate slope (make a table of points from your line and/or use a slope triangle or formula).

5. Define your variables. 6. Find the equation for your LINE : y = a + bx

On Penny’s 15th birthday her grandmother gave her a large jar of quarters. Penny decided to continue saving quarters in the jar. Every few months she counts her quarters and records the number in a table. Predict how many quarters Penny will have on her 18th birthday.

1)Make a scatter plot of the data.2)Draw a line of best fit. Find the slope, y-intercept and an equation.3)Predict the number of quarters she will have on her 18th birthday.

# ofmonths 3 5 8 12 15 19 22 26# of quarters 270 275 376 420 602 684 800 830

Use your equation to predictUse your equation to answer questions:

THINK ABOUT YOUR VARIABLES!! what does x represent? what does y stand for?

Handout

Practice Finish for homework

debrief

what did you learn today?